A successful golf swing is composed of a complex but precise interaction of many components, including proper stance and address of the ball, grip of the club handle, speed of the backswing, position and lack of movement of the head, placement of the rear elbow relative to the body, forward rotation of the hips during the initial portion of the downstroke, pronation of the wrist and hands during the downstroke and as the club strikes the ball, and followthrough. Even a minor variation in any of these components can drastically alter the direction and length of travel of the golf ball. Not surprisingly, the swing of almost all golfers is less than optimal. Perhaps the most universal problem of golfers is the tendency to "slice" or "push" the ball so that the ball curves to the right (for a right-handed golfer) rather than traveling in a straight line. The most common causes of a slice include the swinging of the club in an "outside-in" arc and the improper or lack of pronation of the wrists during the swing. Other golfers suffer from an excessive hook swing causing the ball to travel to the left of the center of the fairway. The usual causes of the hook swing are an overly pronounced "inside-out" swing and excessive pronation of the wrists during the down swing and when striking the ball.
In the past, numerous devices have been developed to assist a golfer to achieve a proper swing. One such type of device is composed of an elongated arm extending upwardly from a horizontal carrier arm clamped to the lower portion of the club shaft. A plurality of vertically spaced apart openings are formed in the upright arm to receive a chord or a flexible line through one of the openings. The ends of the chord are anchored by front and rear pins so that the chord forms a straight line at right angles to the club face. This training device is designed to retain the golf club in a straight line as the club is swung rearwardly and then forwardly to strike the ball. While this device may be of some value in assisting a golfer to develop a correct stroke for putting, it cannot be employed in conjunction with irons or woods. An example of this type of training device is disclosed in U.S. Pat. No. 1,536,512.
Another type of golf swing training device is composed of a wing-shaped member having two planar surfaces separated by a central U-shaped channel portion that is clamped to the shaft of a golf club so that the planar surfaces are disposed transversely to the club face. The device generates a substantial amount of air drag during the initial portion of the downstroke. However, the air drag progressively decreases during the down swing as the club head is rotated forwardly, with the drag reaching a minimum at the point that the club head strikes the golf ball. Thereafter, the drag progressively increases during the follow-through. An example of this type of training device is disclosed by U.S. Pat. No. 3,565,444.
Another type of golf swing training device, which is designed to produce an audible sound when the golf club is improperly swung, is disclosed by U.S. Pat. No. 3,776,556. The device is formed with a teardrop-shaped body that is mounted on the lower portion of a club shaft by a bracket assembly so that the larger end of the body is positioned forwardly. Diagonal passageways extend from one side surface to the opposite side surface of the body in crisscross fashion. A relatively low pitched whistle is disposed in one passageway while a relatively high pitched whistle is disposed in the other. The entrances of the passageways are positioned with respect to the larger forward end of the body so that, in theory, movement of the body along its longitudinal axis causes no sound to be produced by the whistles, but motion of the body along a line oblique to its longitudinal axis causes one of the two whistles to sound.
A further type of golf swing training device is constructed generally in the form of a tailwing of an airplane and is mounted to the upper surface of the head of a driver to help direct the club head during the swing. In one form of the device, a cable mechanism is provided to rotate the tailwing type member about a vertical axis to, in theory, assist in altering the lateral orientation of the club head while striking the ball. In a second form of the training device, an electrical apparatus is employed to rotate the tailwing type member relative to the club head. An example of this type of training device is disclosed by U.S. Pat. No. 3,829,102.